diff --git a/src/inc/sdb.h b/src/inc/sdb.h
index b1c07054ca96475695021eee28d453b06ffe80f2..7dd1549f8791b126e6a416a1a2e30ba655fbcd6d 100644
--- a/src/inc/sdb.h
+++ b/src/inc/sdb.h
@@ -23,7 +23,6 @@ extern "C" {
 #include "taosmsg.h"
 #include "tsdb.h"
 
-extern uint32_t      sdbDebugFlag;
 extern short    sdbPeerPort;
 extern short    sdbSyncPort;
 extern int      sdbMaxNodes;
diff --git a/src/inc/tcache.h b/src/inc/tcache.h
index e8726321f5056b6e208b28c0f99907fe9c0f86d1..93bbf22cd3752589731375a32da3da78c635b956 100644
--- a/src/inc/tcache.h
+++ b/src/inc/tcache.h
@@ -49,10 +49,10 @@ void *taosAddDataIntoCache(void *handle, char *key, char *pData, int dataSize, i
  * if it is referenced by other object, it will be remain in cache
  * @param handle    cache object
  * @param data      not the key, actually referenced data
- * @param remove   force model, reduce the ref count and move the data into
+ * @param _remove   force model, reduce the ref count and move the data into
  * pTrash
  */
-void taosRemoveDataFromCache(void *handle, void **data, bool remove);
+void taosRemoveDataFromCache(void *handle, void **data, bool _remove);
 
 /**
  * update data in cache
diff --git a/src/inc/textbuffer.h b/src/inc/textbuffer.h
index f86e14ec8b87c1fea5701b836fa1a94da43bdf7c..e8f829bb55380f99e4f9e37ea9a5e2b55542c0cd 100644
--- a/src/inc/textbuffer.h
+++ b/src/inc/textbuffer.h
@@ -26,10 +26,10 @@ extern "C" {
 #include "tutil.h"
 #include "taosmsg.h"
 
-#define DEFAULT_PAGE_SIZE 16384  // 16k larger than the SHistoInfo
-#define MIN_BUFFER_SIZE (1 << 19)
-#define MAX_TMPFILE_PATH_LENGTH 512
-#define INITIAL_ALLOCATION_BUFFER_SIZE 64
+#define DEFAULT_PAGE_SIZE               16384  // 16k larger than the SHistoInfo
+#define MIN_BUFFER_SIZE                 (1 << 19)
+#define MAX_TMPFILE_PATH_LENGTH         PATH_MAX
+#define INITIAL_ALLOCATION_BUFFER_SIZE  64
 
 // forward declare
 struct tTagSchema;
diff --git a/src/inc/tkey.h b/src/inc/tkey.h
index e4917423860f0402fa06a7ff05b0e03dfd0ac187..c8b3c87f5e9c6549c23ff1918348c34393bdf63b 100644
--- a/src/inc/tkey.h
+++ b/src/inc/tkey.h
@@ -12,9 +12,12 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
+#ifndef TDENGINE_TKEY_H
+#define TDENGINE_TKEY_H
 
-#ifndef _TAOS_KEY_H_
-#define _TAOS_KEY_H_
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include <stdbool.h>
 #include <stdint.h>
@@ -27,4 +30,8 @@ char *base64_encode(const unsigned char *value, int vlen);
 char *taosDesEncode(int64_t key, char *src, int len);
 char *taosDesDecode(int64_t key, char *src, int len);
 
+#ifdef __cplusplus
+}
 #endif
+
+#endif
\ No newline at end of file
diff --git a/src/inc/ttypes.h b/src/inc/ttypes.h
index 8b31a446d30ba405d56e9a767dee5dc274064ce8..b0f8044404a40a0e85ac90d3df4ae5f9ad0d7e35 100644
--- a/src/inc/ttypes.h
+++ b/src/inc/ttypes.h
@@ -53,8 +53,7 @@ void setNullN(char *val, int32_t type, int32_t bytes, int32_t numOfElems);
 void assignVal(char *val, char *src, int32_t len, int32_t type);
 void tsDataSwap(void *pLeft, void *pRight, int32_t type, int32_t size);
 
-// variant, each number/string/field_id has a corresponding struct during
-// parsing sql
+// variant, each number/string/field_id has a corresponding struct during parsing sql
 typedef struct tVariant {
   uint32_t nType;
   int32_t  nLen;  // only used for string, for number, it is useless